Today efficient provision of energy is crucial, and since non-renewable sources of energy will eventually be depleted, we must transition to other, renewable sources. The four main sources of non-renewable energy today are oil, natural gas, coal and nuclear energy – some of which also have a substantial negative impact on the environment. However, there are cleaner options – renewable energy, that naturally will not run out or be depleted. The main sources today are wind energy, hydropower, biomass, geothermal energy, and of course, solar energy.